Grating and like structure



H. s. NAGIN `@RATING AND LIKE STRUCTURE Filed Nav. t"so, 1958 Feb. 13, A1940.

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Patented Feb. 13, 1940 `UNITED STATES www PATENT OFFICEy 2,190,215 i GRATING AND LIKE STRUCTURE Application November so, 193s, serai No. 243,141

9 Claims.

This invention relates to gratings and like structures and is particularly applicable to gratings of the socalledopen mesh type which are used for flooring in bridges, runways and in other 5 locations and which directlysupport the trailic without the aid of a reenforcing illling or a continuous substructure. If desired, however, the structure can be used in a reenforced concrete structure. This application is a modication of l0 my co-pending application, Serial No. 170,587, for Gratings and like structures, filed October 23, 1937.

In certain installations of traffic supporting roadways, such as are employed in bridges, the

15 oor, or deck on which the trafiic is borne is constructed of metal open mesh gratings or grids which are supported directly on a skeleton sup-` porting structure, .such as the sills or stringers of the bridge. Such oors are in general con- 90 structed from sectional units or slabs which are usually later welded or riveted, in the field, together to form a continuous structure. Each unit is, in general, made of spaced apart bearer 'bars which span the space between the stringers or sills, the bearer bars in turn being secured together at their tops by transverse bars. The tops of the cross bars and bearer bars are usually in the same plane. The grating or flooring presents a cell-like surface to the traiilc and this reticulated traic sustaining floor `has proved to be quite successful in use. It is substantially skid-proof and highly wear-resistant and at the same time it forms a structure which is much lighter than any known continuous surface structure, such as a reenforced ooring, and this permits the bridge or structureto be economical- 1y designed and fabricated, due to the greatly lessened dead load of the iioor. Due to the meshlike structure, the flooring is self-cleaning, and

there is but little likelihood oi snow and ice accumulating on the oor to increase the dead load, or to cause skidding.

It is apparent that any lessening of the weight of the oor and the dead loads`imposed thereon will enable a lighter supporting structure to be employed without any sacrice in the strength of the structure, thus serving to reduce the cost of the completed structure without in any degree impairing the ability of the iioor and structure lo to carry the loads imposed thereon.

The openings in an open type grating preferably should not be to large, as vehicles, partic'ularly those with smaller wheels, will not smoothly pass yover large openings. Where the u stringers run longitudinally of the bridge and (Cl. 18S-82) the open mesh flooring rests directly on the lstringiers, it is obvious that the bearer bars must run transverse to the roadway and for the reasonswhich I have given. the bearer bars must not be'too widely spaced from one another. l Furthermore, it is essential that the structure be strong and the deflection or the flooring be at a minimum. The deflection is inversely proportional to the cube of the depth, and it is evident that it is desirable to have the main l. bearer bars as deep as possible.` certain minimum thickness of metal is necessary to allow for corrosion and in many instances if the bearer bars are of an economical size and prlierly spaced, the structure will beyunduly heavy and u unnecessarily strong. Such a structure is costly and uneconomical. If sumcient bearer bars of the necessary strength and stiffness are employed to carry the load, and intermediate bars are includedto enable the size of the openings to be .n of' a. desirable size, and means are employed to transmit the load .from the intermediate bearer bars to the main bearer bars, the resulting structure will be i'ree from the aforementioned objections. .s

One of the objects of my invention is to provide an open mesh flooring which will embody a maximum strength and a minimum oi' metal and provide cell-like openings of a desirable size. I accomplish this by using a number of spaced apart N main bearer bars of a size suiilcient to carry the load to the supporting structure and a number ot intermediate bearer bars of less depth parallel to andl placed between the main bearer bars, the intermediate bearer bars and the main @5 bearer bars being secured at their top portions in substantially the same plane by cross bars which serve to space apart the said bearer bars and to distribute the load, while the bottom portions of the intermediate bars rest on carrier 40 bars which, in turn, are secured to the main bearer bars below the cross bars. Stresses im- DOSed onthe intermediate bearer bars are trans' mitted to the carrier bars and through them to the main bearer bars and thence to the support- 5 ing structure. i

In one form oi' my invention I use main bearer bars connected by interposed zigzag bars which are connected to each other and to the main bearer bars preferably by riveting. 'Ihe strains 50 imposed on the bent bars are transmitted largely to a carrier bar which is arranged transversely to the main bearer bars. In all forms of the modiiications `shown in this application, bent bars are employed and they are preferably le- 6 5 l cured by riveting, as this form of construction is desired by some engineers.

By the use of structures made according to my invention, it is possible to advantageously design the floor so that it rests directly on fairly widely spaced supporting members. For example, the floor may rest on the stringers of a bridge, withvout the use of sills or substringers interposed between the stringers and the oor. This enables a simpler design to be utilized, as well as worthwhile reductions to be made in the weight of the bridge, and consequently in the cost thereof.

I provide a structure wherein the amount of material employed is at a minimum, while at the same time the strength and stiiness of the structure is unimpaired. The structure is strong and stiff and of lighter weight than any similar structure of like strength and stiffness that I know of. My structure is relatively simple and inexpensive to build, may be fabricated and placed in position with ease, and provides an excellent tramo surface.

In the accompanying drawing, where I have shown for purposes of illustration the present preferred embodiment of my invention:

Figure 1 is a fragmentary plan View of a portion oi a unit;

Figure '2 is a vertical sectional view along thev line II-lI of Figure l;

Figure 3 is a vertical sectional view of another form of a unit;

lFigure 4 is a plan view of a portion of the unit shown inv Figure 3; and Figure 5 is, a vertical section of still another form of a unit. 1

For ease in fabrication and erection I prefer to construct my gratings of metal in units of a convenient size, which units are later placed in position on the supporting structure in the field and if an area larger than an individual unit is to be covered, a desired number of units are employed and the adjoining units are welded to each other and to the supporting structure, which may well be the stringers or the sills of a bridge or floor beams in other structures.

In the drawing, I have shown in Figures 1 and 2 a fragmentary view of a unit made up of metallic elements which comprises a number of parallel and spaced apart longitudinally extending main bearer bars 2 of generally inverted' T-section, the web of 'which extends vertically. The bars are of suflicient area to resist the stresses which will be imposed thereon. Between the main bearer bars 2 and parallel thereto are rectangular intermediate bearer bars 3 of considerably less depth than the main bearer bars and disposed edge up. The main bearer bars 2 and the intermediate bearer bars 3 are connected ad- Joining their tops to form a grating of the deaired mesh by zigzag bars or bent bars having diagonal portions 5 which extend between the main bearer bars and the intermediate bearer bars, and flat portions G which bear against the sides of the said bars 2 and 3. The fiat portions B of adjacent zigzag bars overlap the opposite sides of the main bars 2 and the intermediate bars 3 in the same region. The zigzag bars 4 are of less depth than the intermediate bearer bars 3. The tops of the main bearer bars 2, the intermediate bearer bars 3 and the zigzag bars Il are in substantially the same plane. The arrangement of the bars and connecting zigzag bars facilitate their assembly and joinder in the overlapping regions, preferably by riveting to form an integral structure. It is. of course, underareaal@ stood that other means of fastening may be employed, such as spot welding.

The intermediate bearer bars 3, which are of less depth than the main bearer bars 2, extend to and are supported on the carrier bars l which pass through slots 8 in the webs of the xnain bearer bars 2. The intermediate bearer bars are welded to the carrier bars 'I and the carrier bars I are welded to the webs of the main bearer bars 2.

In the form of the invention shown in Figures 8 and 4, the main bearer bars 9 are of modified railroad rail section and have a bottom flange I and a head portion II connected by a web I2. When main bearer bars of this shape are employed, it is essential that the flat portions of the zigzag or bent bars I3, which t against the main bearer bars, be reduced in vertical section from the top at I4 so as to fit under the head portion II. The ilat portions I5 which iit against the intermediate bearer bars I6 are uninterrupted in section. 'I'he intermediate bearer bars 'are of rectangular section, are of considerably less depth than,y the main bearer bars and are placed edgewise in the structure. Of course the intermediate bearer bars could have a section other than rectangular. The tops of the main bearer bars, the intermediate bearer bars and the umeduced portions of the zigzag bars are in the same plane. The zigzag bars I3 are connected to the main bearer bars 9 and the intermediate bearer bars I 6 preferably lby riveting. Through the webs I2 of the main bearer bars a carrier bar I1 is passed through appropriate slots. The intermediate bearer bars I6 which are of less depth than the main bearer bars 9 rest on the carrier bar IIand are preferably welded thereto. The bottom of the carrier bar I'I is above the bottom portion 'of the main bearer bars 9. lIn the modification shown in Figure 5, the main bearer bars IB are of inverted T-shape standing on edge and are spaced apart in parallel relation. The main bars I8 are connected by two adjoining zigzag bars I8 and 20 of rectangular section and of less depth than the main bars. The zigzag bars have diagonal portions 2I and flat portions 22, as have the bars shown in Figure 1. The zigzag bars I9 and 20 contact at the alternate flat portions 2| and are secured together, for example, by riveting. The other alternate fiat portions overlap the main bearer bars I8 and fiat portions of adjacent zigzag bars 23 and are secured together by riveting. It will be observed that there are no intermediate bearer bars in this construction. Carrier bars 24 pass through slots in the webs of the main bearer bars I8 and are preferably welded to the main bearer bars. The carrier bars 24 contact the bottoms of the zigzag bars I9 zand 20, and support them. The carrier bars are disposed at suitable intervals along the length of' the main bearer bars I8. The bottom of the carrier bars is above the bottom oi' the main bearer bars I8. The tops of the main bearer bars and of the zigzag bars are i the same plane. l

My invention provides novel reenforcing means by which bars of relatively shallow depth may be utilized to the maximum of their supporting capacity. While the structure which I have described is particularly applicable to ooring of the open mesh type, it can also be employed as a reenorcement for concrete slabs. I also contemplate that the unit may have incorporated with it a plastic lling material over the whole or any part of the surface and to any depth, as

of material used to carry a vgiven load yunder given conditions. In a structure made according to my invention the main lbearer bars serve to transmit the loads to the `supporting structure.l The loads imposed on lthe intermediate,bearer,` bars are naturally transmitted to" the carrier bars and thence to themain bearer bars and fromk the main bearer harsto the supporting struc-j ture. i

ferred embodiment of my invention, itwill be understood `that the invention is `not limited thereto but may be otherwise embodied and practiced within the scope of the'following claims.`

1. A grating structure of the class described composed oi' units joined togetherto form a continuous structure, each `unit including at` last three, longitudinally extending main bearer bars in spaced relation, zigzag bars having diagonal portions and ilattened portions connecting said main bearer bars and of less depth than and disposed between each pair of the main bearer bars, the alternate flattened portions of the zigzag bars contacting the sides of the main bearer bars and being secured thereto, the tops of the zigzag bars and the main bearer bars lying in the same plane, `and carrier bars transversely passing through said main bearer bars, the upper edges of the carrier bars being in contact with the lower edges of the zigzag bars and supporting the zigzag bars at intervals, the bottoms of the carrier bars being above the bottoms of the main bearer bars.

2. A grating structure of the class described composed of units joined together to form a continuous structure, each unit including at least three, longitudinally extending main bearer bars in spaced relation, zigzagbars having diagonal portions and flattened portions connecting said main bearer bars and of less depth than and disposed between each pair of the main bearer bars, the alternate ilattened portions. oi' the zigzag bars contacting the sides of the main bearer bars and secured thereto, the tops of the zigzag bars and the main bearer bars lying in the same plane, and transverse carrier bars extending between and connected to said main bearer bars, the upper edges of the carrier bars being in contact with the lower edges of the zigzag bars and i supporting the zigzag bars at intervals, the bottoms of the carrier bars being above the bottoms of the main bearer bars.

3. A grating structure of the class described composed of units joined together to form a continuous structure, each unit including at least three, longitudinally extending main bearer bars in spaced relation, a plurality of zigzag bars having diagonal portions and flattened portions connecting said main bearer bars and of less depth than and disposed between each pair of the main bearer bars, certain of the attened portions of one zigzag bar bearing against and being secured to the main bearer bar and certain of the other flattened portions being secured While I have illustrated and described the pre1 to the attened portions of the adjoining zigzag bar, and carrier bars extending between and secured to the said main bearer bars, the upper edges of the carrier bars being in contact with the-lower edges of the zigzag bars at intervals, 5'

the bottoms of the carrier bars being 4above the i bottoms of the main bearer bars.

` 4. A grating structure of the class described `composed of units'joined together to form a continuous structure, each unit including at least 10 three, longitudinally extendingmain bearer bars l in spaced relation, a plurality or zigzag bars having diagonal portions and flattened portions connecting `said maingbearer bars and oi less depth thanr and disposed between each pair ofthe main 15 ybearer bars, certainy of the :flattened portions ot :one zigzagbar bearing against and being secured to the main bearer bar and certain of the other fiattened portions being secured to the flattened portions of the adjoining zigzag bar, and carrier zo bars transversely passing through aligned slots in said main bearer bars, the upper edges of the carrier barsbeing incontact with the lower edges Aoff and supporting the zigzag bars atintervals,

the bottoms of the* carrier bars being abovethe 25 bottoms ofthe main bearer bars.

5. AV gratingstructure of the class described composed of units joined together to form a continuous structure, each unit comprising at least three, longitudinally extending main bearer w Ibars in spaced relation, at least one longitudinal- 1y extending intermediate bearer bar parallel to l and spaced apart and of less vertical depth than the main bearer bars disposed between each pair of main bearer bars. zigzag bars connecting said l5 main bearer bars and intermediate bearer-bars and secured thereto, the tops of said main bearer bars, intermediate bearer `bars and. zigzag bars being in the same plane, and carrier bars passing transversely through said main bearer bars, o

the upper edges of the carrier bars being in contact with and supporting the lower edges of the intermediate bearer bars, the bottoms of the carrier bars being above the bottoms of the main bearer bars.

6. A grating structure of the class described 45 composed of units joined together to form a continuous structure, each unit comprising at least three, longitudinally extending main bearer bars in spaced relation, at least one longitudinally so extending intermediate bearer bar parallel to and spaced apart and of less vertical depth than the main bearer bars disposed between each pair of main bearer bars, zigzag bars connecting said main bearer bars and intermediate bearer bars and secured thereto and of less vertical depth than the intermediate bearer bars, the tops of said main bearer bars, intermediate bearer bars and zigzag bars being in the same plane, and carrierbars passing transversely through said main bearer bars below the top and above the bottom of each of the main bearer bars, the upper edges of the carrier bars being in contact with and supporting the lower edges of the intermediate bearer bars, the bottoms oi the carrier bars being above the bottoms of the main bearer bars.

7. A grating structur of the class described composed ci' unitsjoined together to form a continuous structure, each unit comprising at least three, longitudinally extending main bearer bars 70 of inverted T-section arranged in parallel spaced relation, at least one longitudinally extending intermediate bearer bar parallel to and spaced apart and of less vertical depth than the main bearer bars disposed between each pair of main 75 bearer bars, zigzag bars disposed between said main bearer bars and intermediate bearer bars and secured thereto and of less vertical depthtv than the intermediate bearer bars, the tops of said main bearer bars, intermediate bearer bars and zigzag bars being in the same plane, and carrier bars passing transversely through said main bearer bars, the upper edges of the carrier bars being in contact with and supporting the lower edges of the intermediate bearer bars, the bottoms of the carrier bars being above the bottoms of the main bearer bars.

8. A grating structure of the class described composed of units joined together to form a continuous structure, each unit comprising at least three, longitudinally extending main bearer bars having a head portion and a foot portion connected by vertical webs in spaced parallel relation, at least one longitudinally extending intermediate bearer bar parallel to and spaced apart from and of less depth than the main bearer bars disposed between each pair of main bearer bars, zigzag bars disposed between said main bearer bars and said intermediate bearer bars and secured thereto, said zigzag bars having diagonal portions and attened portions, said fiattened portions being of reduced vertical depth where the flattened portions of the zigzag bars adjoin the main bearer bars so as to accommodate the head of the main bearer bars, the tops of said main bearer bars, the unreduced aimais portions of the zigzag bars and the tops of' the intermediate bearer bars being in the same plane, and carrier bars passing transversely through said main bearer bars, the upper edges of the carrier bars being in contact with and supporting the lower edges of the intermediate bearer bars, the bottoms of the carrier bars being above the bottoms of the main bearer bars.

9. A grating structure of the class described composed of units joined together to form a continuous structure, each unit comprising at least three, longitudinally extending main bearer bars in spaced parallel relation, zigzag bars having diagonal portions and flattened portions connecting the main bearer bars and of less depth than and disposed between each pair of the main bearer bars, the alternate iiattened portions of the zigzag bars contacting the sides of the main bearer bars and secured thereto, the tops of the zigzag bars and the main bearer bars lying in the same plane, and means below the zigzag bars for transmitting stresses from the zigzag bars to the main bearer bars, said means including carrier bars extending transversely between the main bearer bars and secured thereto, the bottoms of the carrier bars being above the bottoms of the main bearer bars and the tops of the carrier bars being in contact with the lower edges of the zigzag bars.

HARRY S. NAGIN. o 

